const TOKEN_KEY = 'kairo_auth_token'

export { TOKEN_KEY }

export function getToken() {
  return localStorage.getItem(TOKEN_KEY) || ''
}

export function setToken(token) {
  if (token) localStorage.setItem(TOKEN_KEY, token)
  else localStorage.removeItem(TOKEN_KEY)
}

export function apiHeaders(token = getToken()) {
  const headers = { 'Content-Type': 'application/json' }
  if (token) headers['X-Auth-Token'] = token
  return headers
}

export function parseError(body, fallback) {
  if (!body) return fallback
  if (typeof body.detail === 'string') return body.detail
  if (Array.isArray(body.detail)) {
    return body.detail.map((d) => d.msg || JSON.stringify(d)).join(', ')
  }
  return fallback
}

export async function apiFetch(path, options = {}) {
  const token = options.token ?? getToken()
  const res = await fetch(path, {
    ...options,
    headers: { ...apiHeaders(token), ...options.headers },
  })
  const body = await res.json().catch(() => null)
  if (!res.ok) {
    const message = parseError(body, `Anfrage fehlgeschlagen (${res.status})`)
    const err = new Error(message)
    err.status = res.status
    err.body = body
    throw err
  }
  return body
}